In the early years of the 20th century, the Rhodes' British South Africa Company did little in Northern Rhodesia. Its minerals were not nearly as accessible or valuable as those in Southern Rhodesia, and little protection or aid actually materialised. It became viewed by the colonials as a source of cheap labour for the mines of South Africa and Southern Rhodesia.
To facilitate this, taxes were introduced for the local people, which effectively forced them to come into the cash economy. Virtually the only way for them to do this was to find work in one of the mines further south. By 1910 a railway linked the mine at Kimberley, in South Africa, with Victoria Falls and beyond, making long-distance travel in the subcontinent more practical.
Meanwhile the cost of administering and defending the company's interests was rising, and in 1923 Southern Rhodesia became self-governing. In 1924 the British Colonial Office took over administration of Northern Rhodesia from the British South Africa Company, though the mining rights remained with the Company. The Colonial Office then set up a legislative council to advise on the government of the province, though only a few of its members came from outside the administration.
Shortly afterwards, in 1928, huge deposits of copper were located below the basin of the upper Kafue, under what is now known as the Copperbelt. Over the next decade or so these were developed into a number of large copper mines, working rich, deep deposits of copper. World War II demanded increased production of base metals, and by 1945 Northern Rhodesia was producing 12% of the non-communist world's copper. This scale of production required large labour forces. The skilled workers were mostly of European origin, often from South Africa's mines, whilst the unskilled workers came from all over Northern Rhodesia.
Wages and conditions were very poor for the unskilled miners, who were treated as migrant workers and expected to go home to their permanent villages every year or so to 'recover'. Death rates among them were high. Further, the drain of men to work the mines inevitably destabilised the villages, and poverty and malnutrition were common in the rural areas.